Reliability and Validity of a Mobile Device for Assessing Head Control Ability

Purpose: Head control ability assessed by the cervicocephalic kinesthetic sensibility test has been widely used as an important indicator for the diagnosis or treatment of cervical disorders. However, a reliable and handy device to measure head control has not been developed. This study aimed to compare the capability to quantify the cervicocephalic kinesthetic sensibility between an ultrasound-based motion capture system and an inertial measurement unit-based (IMU-based) mobile device with the ultimate goal of developing a clinically-useful assessment tool. Methods: Thirty-five young healthy volunteers were recruited in this study. The subjects were asked to perform the clinical cervicocephalic kinesthetic sensibility test in a head-to-neutral reposition procedure. The maximal range of motion and the reposition test in the cervical flexion, extension, right rotation, and left rotation directions were analyzed. After 5–7 days, the experimental procedure was repeated for the between-day retest measurement. Results: No significant differences in cervical maximal range of motion and head reposition errors between the two devices were found. The intra-rater reliability of both ranged from good to excellent for the within-day and between-day measurements. The correlation between the two devices was also high, with r-values higher than 0.7 in all movement directions. Conclusions: The IMU-based mobile device shows the potential to be a reliable and feasible head assessment device. Further study is warranted to extend its applications for clinical examination.